At least those who were worried about their white direhorns changing will be set at ease by this news. :) And hey, at least the babies are even better eye candy now: there are more colors!
Hey guys, quick update from Kalliope on the 5.3 PTR. As expected, the baby direhorns are now marked as friendly to players, so they can no longer be tamed. All existing tamed babies on the PTR turned into white direhorns. This not only confirms that no unintended pets will be making it to live servers, but the existing direhorns tamed from here will be unchanged. Oh well, better luck next time, pet seekers!